Do you refer with "wall of sound" to the sound that phil Spector developt or high volume, saturation, distortion in music as describe here under i guess the latest.
No. I refer to a class of auditory illusions related to enlargement of perceived sound sources.
Imagine a single bumblebee flying in a complex pattern at a distance of 2 meters from you. Human hearing system is well-attuned to tracking the direction to such sound object - you can close your eyes and still "see" it with your ears.
Now imagine a dozen of them flying in a general vicinity of a point at the same distance. This time around, your hearing system will perceive a larger, relatively firmly positioned, object in space, instead of individual bumblebees.
Similarly, if a sound reproduction system + room combination creates multiple sound images of a true sound object, the result could be an illusion of a larger object, with timbral characteristics similar to the true sound object.